Improve read_raw file extension detection

[cbrnr]

Fixes #11515.

[cbrnr]

I would like to update our tests and try to read a file with multiple dots. For efficiency reasons, I'd like to use an existing file (e.g. mne/io/edf/tests/data/test.edf) and rename it temporarily. What would be the preferred way to do that (i.e. should I use tmp_path from pytest or some MNE-specific object, and should I use shutil.copy() to copy and rename the EDF file)?

[agramfort]

can you add a test_split_name_ext function?

thx @cbrnr

[cbrnr]

Done, ready for review.

[larsoner]

What would be the preferred way to do that (i.e. should I use tmp_path from pytest or some MNE-specific object, and should I use shutil.copy() to copy and rename the EDF file)?

Yes a copyfile using tmp_path is usually what we do. Marking as changes requested so we don't forget this part!

[cbrnr]

Done @larsoner!

[larsoner]

Just a couple of nitpicks that don't really matter (take or leave them) plus a test enhancement that I think is worthwhile

[cbrnr]

All done!

[larsoner]

Thanks @cbrnr !